I'm doing a screenshot of a portion of the screen by this code :
-(UIImage *) takePic {
UIGraphicsBeginImageContextWithOptions(self.view.bounds.size,YES, 0.0);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
CGRect rect = CGRectMake(20,238 ,600 , 532);
CGImageRef imageRef = CGImageCreateWithImageInRect([viewImage CGImage], rect);
UIImage *img = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
return img;
}
This works well, but it takes too much time, since I'm taking the imageContext of the entire Self.View.bounds first then retake a small CGRect from.
How can I improve my code to get the method running faster? thanks.
Related
I tried two different ways to create a screenshot, but unfortunately they don't work as I need, I have an RMMapView that is blank on the screenshot. When I create snapshot manually on my device it works perfectly, and the map view is on the screen. So I would like to achieve the same result programmatically. Is it possible somehow as I tried? Or what is the right way to do that? (To reproduce that type of screenshot)
- (UIImage *) takeScreenshot {
//1. version
UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, NO, [UIScreen mainScreen].scale);
[self.view drawViewHierarchyInRect:self.view.bounds afterScreenUpdates:YES];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
//2. version
UIGraphicsBeginImageContext(self.view.bounds.size);
CGContextRef context=UIGraphicsGetCurrentContext();
[self.view.layer renderInContext:context];
UIImage *image=UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
Actually You can use a method called takeSnapshot in a RMMapView.
UIImage *image = self.mapView.takeSnapshot
[Update]
Can you try this method instead
CGSize size = self.view.bounds.size;
CGRect cropRect = self.mapView.bounds
UIGraphicsBeginImageContext(size);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage * mapImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGImageRef imageRef = CGImageCreateWithImageInRect(mapImage.CGImage, cropRect);
UIImage * cropImage = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
UIImageWriteToSavedPhotosAlbum(cropImage, nil, nil, nil);
UIGraphicsEndImageContext();
Good luck
I can take snapshots of the whole frame of the UIView with no problem.
Taking part of it cause to a squeezed image.
This is my UIView category method:
- (UIImage *)snapshot:(CGRect)frame
{
UIGraphicsBeginImageContextWithOptions(frame.size, YES, [[UIScreen mainScreen] scale]);
[self drawViewHierarchyInRect:frame afterScreenUpdates:YES];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return image;
}
And this is the call to this method:
UIImage *img = [self.view snapshot:bottomRectToSnap];
When bottomRectToSnap is a partial frame of the view.
Note:The UIView contains UITableView if that matter.
The code you are applying is fine.
Need to add some logic, whatever part you need to take snap, It should be available on screen and hide rest of part while snapping.
Once snap shot done, remove hide code. So it will not effect to view interface too.
Use the following code.
- (void)captureView:(UIView*)view withFrame:(CGRect)frame{
UIGraphicsBeginImageContext(self.view.bounds.size);
[view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGRect rect = frame;
CGImageRef imageRef = CGImageCreateWithImageInRect([viewImage CGImage], rect);
UIImage *img = [UIImage imageWithCGImage:imageRef];
UIImageWriteToSavedPhotosAlbum(img, nil, nil, nil);
CGImageRelease(imageRef);
}
You can add this code to take the snapshot of particular part..
CGRect cropRect=CGRectMake(0, 0, 100, 100);
CGImageRef imageRef = CGImageCreateWithImageInRect([_galleryimageview.image CGImage], cropRect);
UIImage *cropedImage=[UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
This code crop the part of particular image ...Hope this is helpfull for you..
Been trying to fix this problem all day to no avail.
Pretty much, I'm taking a screenshot of the view, then trying to crop out the first 50px and a footer. Problem is that when I do this, the result is a little blowed up, and quality is lost. Here's what I wrote, which I think conforms to retina.
-(UIImage *)takeSnapShotAndReturn{
//Take screenshot of whole view
if([[UIScreen mainScreen] respondsToSelector:#selector(scale)]){
UIGraphicsBeginImageContextWithOptions(self.view.bounds.size,NO,[UIScreen mainScreen].scale);
}
else{
UIGraphicsBeginImageContext(self.view.window.bounds.size);
}
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
combinedImage = [self cropOutArea:image withRectangle:CGRectMake(0, 50, 320, 467)];
UIImageWriteToSavedPhotosAlbum(combinedImage, nil, nil, nil);
UIGraphicsEndImageContext();
return image;
}
-(UIImage *)cropOutArea:(UIImage*)image withRectangle:(CGRect)rectangle{
if(image.scale > 1){
rectangle = CGRectMake(rectangle.origin.x * image.scale,
rectangle.origin.y * image.scale,
rectangle.size.width * image.scale,
rectangle.size.height * image.scale);
}
CGImageRef imageRef = CGImageCreateWithImageInRect(image.CGImage, rectangle);
UIImage *result = [UIImage imageWithCGImage:imageRef scale:image.scale orientation:image.imageOrientation];
CGImageRelease(imageRef);
return result;
}
I find cropping extremely confusing!
I'm not sure EXACTLY what you're trying to do, but this may be it .....
-(UIImage *)simplishTopCropAndTo640:(UIImage *)fromImage
// moderately optimised!
{
float shortDimension = fminf(fromImage.size.width, fromImage.size.height);
// 1.use CGImageCreateWithImageInRect to take only the top square...
// 2. use drawInRect (or CGContextDrawImage, same) to scale...
CGRect topSquareOfOriginalRect =
CGRectMake(0,0, shortDimension,shortDimension);
// NOT fromImage.size.width,fromImage.size.width);
CGImageRef topSquareIR = CGImageCreateWithImageInRect(
fromImage.CGImage, topSquareOfOriginalRect);
CGSize size = CGSizeMake( 640,640 );
CGRect sized = CGRectMake(0.0f, 0.0f, size.width, size.height);
UIGraphicsBeginImageContextWithOptions(size, NO, 0.0f);
CGContextRef cc = UIGraphicsGetCurrentContext();
CGContextSetInterpolationQuality(cc, kCGInterpolationLow);
CGContextTranslateCTM(cc, 0, size.height);
CGContextScaleCTM(cc, 1.0, -1.0);
CGContextDrawImage(cc, sized, topSquareIR );
// arguably, those three lines more simply...
//[[UIImage imageWithCGImage:topSquareIR] drawInRect:sized];
CGImageRelease(topSquareIR);
UIImage *result = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
result =
[UIImage imageWithCGImage:result.CGImage
scale:result.scale
orientation: fromImage.imageOrientation];
//consider...something like...
//[UIImage imageWithCGImage:cgimg
// scale:3 orientation:fromImage.imageOrientation];
return result;
}
Consider also this valuable category .....
-(UIImage *)ordinaryCrop:(CGRect)toRect
{
// crops any image, to any rect. you can't beat that
CGImageRef imageRef = CGImageCreateWithImageInRect([self CGImage], toRect);
UIImage *cropped = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
return cropped;
}
Finally don't forget this if you're using the camera "the most useful code in the universe!" iOS UIImagePickerController result image orientation after upload
Hope it helps somehow
Try setting this BOOL property before releasing result in cropOutArea.
result.layer.masksToBounds = YES
is there an easy way of selecting a region of an UIImage Instance and then creating a new image out of it? I tried it using a pan-gesture Recognizer for getting the coordinates that the user selected. But with this option there is now visible feedback and i also have to transform the coordinates. Is there maybe a nice plugin or best practices for doing this ?
try this:
UIGraphicsBeginImageContext(self.view.bounds.size);
// retrieve the current graphics context
CGContextRef context = UIGraphicsGetCurrentContext();
// render view into context
[self.view.layer renderInContext:context];
// create image from context
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
image=[self cropImage:image];
UIGraphicsEndImageContext();
- (UIImage *)cropImage:(UIImage *)oldImage {
CGSize imageSize = oldImage.size;
UIGraphicsBeginImageContextWithOptions(CGSizeMake( imageSize.width,imageSize.height - 150),NO,0.); //set your height and width
[oldImage drawAtPoint:CGPointMake( 0, -80) blendMode:kCGBlendModeCopy alpha:1.];
UIImage *croppedImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return croppedImage;
}
Like this:
CGImageRef imageRef = CGImageCreateWithImageInRect([bigImage CGImage], cropRect);
UIImage *croppedImage = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);
I'm trying to get a UIView screen capture on iOS.
In my view I have two UIImageView with animations.
The code that I using it to capture the view is:
UIGraphicsBeginImageContextWithOptions(self.view.bounds.size, NO, 1.0);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
// Read the UIImage object
UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
UIImageWriteToSavedPhotosAlbum(image, self,
#selector(image:didFinishSavingWithError:contextInfo:), nil);
The result is an image with the background and only one UIImageView. Both ImageViews are in moviming all the time. If I take several pictures, then the UIImageView is in the same position each time.
Try this one:
-(CGImageRef)imageCapture
{
UIGraphicsBeginImageContext(self.view.bounds.size);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGRect rect= CGRectMake(0,0 ,width, height);
CGImageRef imageRef = CGImageCreateWithImageInRect([viewImage CGImage], rect);
return imageRef;
}
use the below line whenever you want to capture the screen
UIImage *captureImg=[[UIImage alloc] initWithCGImage:[self imageCapture]];